Open Source Video Upscaler
The trap in video upscaling is judging a model by a single frozen frame. An upscaler does not recover detail that was never captured; it infers plausible detail, and a still that looks razor-sharp can shimmer, crawl, and reinvent itself the moment the footage moves. Temporal stability across motion matters more than peak sharpness on one frame. Open source tools help here because you can test that honestly on your own clips, running the AI locally on your own hardware instead of shipping unreleased cuts or private archives to a metered cloud GPU. The source never leaves the room, and the only ceiling on how much you process is the machine in front of you.
Upscayl
Free and open source AI image upscaler for Linux, macOS, and Windows
Anime4K
Open-source real-time anime upscaling and denoising algorithms for watching 1080p anime on 4K screens
Video2X
Machine learning video super resolution and frame interpolation for Windows, Linux, and containerized use
waifu2x-ncnn-vulkan
GPU image upscaler and denoiser using ncnn with Vulkan on Intel, AMD, NVIDIA, and Apple Silicon
QualityScaler
Windows AI app for image and video upscaling, denoising, and stop-and-resume video processing
REAL Video Enhancer
Video interpolation and upscaling app with TensorRT and NCNN backends
RealScaler
Windows AI upscaler for images and video using Real-ESRGAN, fully offline
Our picks
For producing a file, favor tools built for video; for watching, real-time upscaling avoids re-encoding entirely.
Best flexible video upscaling framework: Video2X Video2X upscales footage and interpolates frames in one framework, driving models including Anime4K v4, Real-ESRGAN, Real-CUGAN, and RIFE, plus custom mpv-compatible shaders. A C and C++ pipeline keeps it fast without extra disk use. It runs on Windows, Linux, and in Docker for headless jobs, needing a Vulkan GPU.
Best for combined upscaling and smoother motion: REAL Video Enhancer REAL Video Enhancer both upscales and interpolates, so it can sharpen 1080p toward 4K and double frame rate in one tool. Scene-change detection keeps cuts crisp, and a live preview shows the latest frame as a job runs. Inference runs on TensorRT, PyTorch, or NCNN across Windows, Linux, and macOS.
Best approachable Windows GUI: QualityScaler QualityScaler enhances, upscales, and denoises both images and video with local AI models and no upload. Automatic tiling fits GPU VRAM limits, multi-GPU is supported, and video jobs stop and resume, which matters on long renders. It needs a DirectX 12 GPU with at least 4 GB of VRAM on Windows.
Best for watching anime in real time: Anime4K Anime4K upscales and denoises anime as it plays, delivered as GLSL shaders for players like mpv, Plex, and IINA. Running during playback, native 1080p looks crisp on a 4K screen with no re-encode and no larger files on disk. It covers line reconstruction, upscaling, deblurring, and denoising.
Choosing an upscaler that holds up in motion
Before anything else, notice that this category mixes two different things. Some tools here upscale still images only: Upscayl and waifu2x-ncnn-vulkan produce sharper photos and graphics, which is useful for animation frames or thumbnails but is not a video pipeline. True video upscalers, including Video2X, REAL Video Enhancer, RealScaler, and QualityScaler, process footage frame by frame and rebuild the clip, which is where temporal artifacts appear. Match the tool to whether you are enhancing pictures or moving footage, because a great image upscaler run naively over video tends to shimmer.
The kind of footage you are rescuing matters as much as the tool. Animation and line art respond very differently from noisy camera originals or old analog captures, and models are usually tuned for one or the other. Anime4K takes an unusual approach worth knowing: it upscales in real time during playback as GLSL shaders in players like mpv, so nothing is re-encoded and no larger file lands on disk, which is ideal for watching but not for producing a deliverable. For that, a model tuned to your source style will beat a general-purpose one.
Then plan around hardware and the full pipeline. Video upscaling is limited by GPU memory and encode time, not raw processor speed, so confirm the tool fits your card: RealScaler and QualityScaler need a DirectX 12 GPU, Video2X requires Vulkan, and REAL Video Enhancer offers TensorRT, PyTorch, and NCNN backends to suit different GPUs. For long jobs, look for tiling, stop-and-resume, and a way to recover a failed frame without restarting a multi-hour render, and confirm audio, subtitles, and color are carried back correctly after the frames are rebuilt.
Related categories
Frequently asked questions
What can a video upscaler actually improve, and what can't it?+
An upscaler raises resolution while inferring cleaner edges and texture than a plain resize would give. It cannot restore information that was never captured, and it may invent plausible detail that is not faithful to the original. The best results come from sources that are soft but not badly compressed. Heavy blockiness, motion blur, blown highlights, and missed focus stay hard problems even with stronger models, so set expectations before a big job.
Which of these tools upscale video, and which only handle images?+
It is worth checking, because the category mixes both. Video2X, REAL Video Enhancer, RealScaler, and QualityScaler process video. Upscayl and waifu2x-ncnn-vulkan upscale still images only, which suits photos, graphics, or individual animation frames rather than clips. Anime4K is different again: it upscales in real time during playback rather than producing a new file. Running an image-only tool over video frame by frame is possible but usually shimmers.
Do I need a particular kind of GPU?+
Usually yes, and the requirement differs by tool. RealScaler and QualityScaler need a DirectX 12 GPU with at least 4 GB of VRAM; Video2X requires a Vulkan-capable GPU; waifu2x-ncnn-vulkan and Upscayl run on Vulkan across Intel, AMD, NVIDIA, and Apple Silicon; and REAL Video Enhancer offers TensorRT, PyTorch, and NCNN backends to match different cards. For many hours of footage, verify hardware support before building a workflow.
How do I stop the output from shimmering or flickering?+
Do not judge quality from still frames. Upscalers that treat each frame independently can generate detail that changes frame to frame, causing crawl on hair, grass, text, and fine patterns. Test with slow pans, fast motion, and fades. Conservative sharpening and lower denoise help, and REAL Video Enhancer adds scene-change detection so cuts stay sharp instead of smearing. Sometimes a slightly less detailed output is simply more watchable.
What is the best option for upscaling anime?+
Anime is a special case with tools tuned for it. For watching, Anime4K upscales 1080p anime to fit a 4K screen in real time as shaders in players like mpv, with no re-encode. To produce a file, Video2X can drive Anime4K v4 and Real-CUGAN models, and REAL Video Enhancer includes anime-focused models such as AnimeJaNai and AniSD. Match the model to the source style for the cleanest line art.
Can these tools also make video smoother, not just sharper?+
Some add frame interpolation, which is separate from upscaling. Video2X runs a filtering mode for upscaling and an interpolation mode using RIFE to raise frame rate, and REAL Video Enhancer interpolates with RIFE, GMFSS, and IFRNet, for example doubling 24 FPS to 48. Interpolation can smooth motion but may introduce its own artifacts on fast or complex scenes, so test it on representative footage.
Does upscaling locally actually protect my footage?+
It can, because the video never has to leave your machine or network, which matters for client work, unreleased media, home videos, and regulated material. RealScaler, QualityScaler, Upscayl, and waifu2x-ncnn-vulkan all state that processing stays on your PC with no upload. Local is not automatically secure, though: check where temporary frames are written, who can reach the machine, and whether logs record sensitive filenames.